from Abhilash Quiz. Question # 9

[Anonymous]

public interface AQuestion
{
void someMethod();
}
The class which implements AQuestion
a. Should have someMethod which must necessarily be public.
b. Should have someMethod which could be "friendly" or public
c. Should have someMethod which should not throw any checked exceptions.
d. Should have someMethod which cannot be sychronized as sychronized is not in the signature of the interface defination.
The answer given is a and c, but IMO answer should be b,c.
can anybody explain, how the answer a is correct.

[Sanjeev Verma]

Dear S
Think of a interface as a INTERFACE, i.e., it has to be available to every user. So a method inside a interface is public and there is no way you can narrow down the access. Hence, answer a is correct.
Hope this helps
Sanjeev

[Anonymous]

Every method declaration in the body of an interface is implicitly public and abstract.

[Rajesh Gupta]

But why it cannot throw checked exception ? Can any body please explain?

[Anonymous]

Implementing interface methods in a class is like overriding methods. And as far as overriding is concerned
1. The overriding and overridden methods must have same return type
2. The accessibility of the overriding method must not be more restrictive than the overridden method
3. The throws clause of the overriding method MUST only specify exceptions ( or less ) that are in the throws clause of the overridden method.
I think 3rd point should clear you doubt.

[Anonymous]

Saying simply, the delaration of a method in an interface should point out all the potencial exceptions the implemented method will throw in all classese that implement the interface.